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Oil is chemistry -- organic chemistry since the polymerization process involves connecting Carbon chains. The logic is attributable to additive clash as stated above. Here is an example. My sample on the right was taken right after I switched oils and the previous oil had an ester cobase stock (PAOs are non polar so need a co base stock to hold additives in suspension). You can see the cross contamination in the oxidation value 29.3 which should be much lower compared to the virgin sample. You can see this sample has wear levels that are twice as high, much higher fuel dilution etc.
Ok, seems like you know what you are doing. I am tempted to go back to liqui molly. Do you think this is wise? I mean 10 quarts in 3 months is a lot. And I said 3000, no, it actually has been 1500 miles.
The highest quality oil you can run in this engine is a metallocene PAO. If the high oil consumption is due to the piston rings being clogged with carbon then no matter which oil you choose there will be consumption (and you will have more blow by which will contaminate the oil faster and cause higher fuel dilution which is bad for engine wear). Running the highest quality oil at short change intervals will be the best thing you can do. This engine is very easy to change the oil with an extractor in 15 mins or less. My engine has 120K miles on it and has no oil consumption problems.
My point about judging an oil is that I often see people say "I was using oil A and then I switched to oil B and the consumption increased, therefore oil A is better" but this sort of logic doesn't make any sense for several reasons. First, the higher consumption could have been due to cross contamination and second, oil consumption isn't a metric that tells you how the oil is protecting your engine. There is nothing wrong with some oil consumption and the key is does the oil consumption increase; oil analysis is needed to tell how well the oil is working. For this reason it makes sense to choose the best oil available and stick with it.
The highest quality oil you can run in this engine is a metallocene PAO. If the high oil consumption is due to the piston rings being clogged with carbon then no matter which oil you choose there will be consumption (and you will have more blow by which will contaminate the oil faster and cause higher fuel dilution which is bad for engine wear). Running the highest quality oil at short change intervals will be the best thing you can do. This engine is very easy to change the oil with an extractor in 15 mins or less. My engine has 120K miles on it and has no oil consumption problems.
My point about judging an oil is that I often see people say "I was using oil A and then I switched to oil B and the consumption increased, therefore oil A is better" but this sort of logic doesn't make any sense for several reasons. First, the higher consumption could have been due to cross contamination and second, oil consumption isn't a metric that tells you how the oil is protecting your engine. There is nothing wrong with some oil consumption and the key is does the oil consumption increase; oil analysis is needed to tell how well the oil is working. For this reason it makes sense to choose the best oil available and stick with it.
you've gone down the oil rabbit hole and are better served by posts on bob is the oil guy forums but I like it.
long story short you've hit the nail on the head. this engine is no stranger to 10K OCIs and they don't seem to be good for the powerplant and long term consumption issues. so change your oil at 5K and call it a day.
It is only a rabbit hole if you don't understand. Most people don't understand chemistry and that is ok, they are not educated on it and that is not their fault. Bob is the oil guy is not a good resource and is full of misinformation. I change my oil every 2-3K miles and it comes out looking pitch black...........
The highest quality oil you can run in this engine is a metallocene PAO. If the high oil consumption is due to the piston rings being clogged with carbon then no matter which oil you choose there will be consumption (and you will have more blow by which will contaminate the oil faster and cause higher fuel dilution which is bad for engine wear). Running the highest quality oil at short change intervals will be the best thing you can do. This engine is very easy to change the oil with an extractor in 15 mins or less. My engine has 120K miles on it and has no oil consumption problems.
My point about judging an oil is that I often see people say "I was using oil A and then I switched to oil B and the consumption increased, therefore oil A is better" but this sort of logic doesn't make any sense for several reasons. First, the higher consumption could have been due to cross contamination and second, oil consumption isn't a metric that tells you how the oil is protecting your engine. There is nothing wrong with some oil consumption and the key is does the oil consumption increase; oil analysis is needed to tell how well the oil is working. For this reason it makes sense to choose the best oil available and stick with it.
I am willing to learn, especially from knowledgeable folks. I switched to Liqi Molly based on recomendations on the forum. I think I needed to add one/two quart between OCI. I then switched to Motul because folks says the oil consumption decreased. In my case it increased. I changed oil in June, drove maybe 1,500 miles and have gone through 10 quarts. So now I am wondering do I go back to Liqui and see if I go back to the old consumption, or give Motul a chance and see if oil consumption increased. But basically I have been adding a quart every 1,000 miles, which seems excessive.
145k mile on a 2018 Q7. Burning 1 quart every 500 miles.
I tried all the oils (motul, amsoil, liqui moly), they all burn.
I`ll pass the car to my wife, who drives less than 5k miles a year...
I complained about excess oil use awhile back. Well, my warranty is paying to replace the pistons while I write this. I will keep track once I get the car back.
Adding QT of oil every 700 miles now (after 70k miles)
Originally Posted by ecbc1
My 2017 Q7's Oil consumption was great. Changed every 5000 miles. But once I passed 75K, I noticed that my oil consumption got progressively worse.
I use to top it off every 4000 miles with 1/2 to 1/4 quart of oil.
Now, after I passed 80K, I need 1/2 a quart every 1500-2000 miles.
The only difference is I'm towing my RV a lot more so I wonder if that impacts oil consumption.
at 80K, I had dealer check out the engine and they didn't see any leaks. They suggested an oil consumption test which I would have to pay for. First part is $247, drive vehicle for 650 miles, and second part is $330 and drive another 650 miles. They take measurements to see if its within their permissible tolerances. So I'm out $$ before they even figure out what to fix.
I went back at 81.5K to have the oil topped off with 1/2 quart.
No way I'm paying $$$ to do an oil consumption test. I guess I'll monitor it for now. Unless anyone knows what else I can look for. I was thinking of hooking up the car to VCDS module and read some numbers but not sure where to read
I have a similar issue. The car has 10,000 extended warranty from Audi and at a dealership shop now. No leaks. They will perform $270 test ( changing oil and taking snapshot of sensors). I need to go back once add oil lights on
08-23-2023, 05:48 PM
